Machine for generating gear wheels



May 7, 1929. H. D. coLMAN w scanm FOR GENERATING GEAR WHEELS Filed March16, 1923 12 Sheets-Sheet l ay 9 9- H. 0-. COLMAN 1,712,254

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MACHINE FOR GENERATING GEAR WHEIEELS Filed March 16, 1923 12 Sheets-Shet 6 May 7, 1929. H. D. COLMAN MACHINE FOR GENERATING GEAR WHEELS 12Sheets-Sheet 7 Filed March 16, 1923 Ii L 1!; 1%) WM HI fizz finial?dYOaAgrJD Lolman 4 Wm w.

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Jigs? H. D. COLMAN MACHINE FOR GENERATING GEAR WHEELS Filed March. 16,1925 12 Sheets-Sheet 12 @WMAW Howardfl o/man 1i atented May 7, 1929.

UNITED STATES PATENT 1,712,254 OFFICE.

HOWARD D. COLLLA IN, F ROCKFORD, ILLINOIS, ASSIGNOR T0 BARBER-COLMANCOM- PANY, OF ROCKFORD, ILLINOIS, A CORPORATION OF ILLINOIS.

MACHINE FOR GENERATING GEAR WHEELS.

Application filcdMarch 16, 1923. Serial no. 625,469.

The object of this invention generally stated, is to render possible theaccurate gen oration of gear wheels, sprocket wheels and similar bodiesof revolution at a relatively rapid rate.

In the accompanying drawings, Figure 1 is a top plan view of a grindingmachine embodying the features of my invention, the dressing mechanismbeing omitted. Fig. 2 is a fragmental side elevation of the machine.Fig. 3 is a fragmental view on an enlarged scale showing one of thegrinding stations. Fig. 4- is a fragmental view illustrating theoperation of grinding one side of each tooth of a blank. Fig. 5 is aview similar to that of Fig. 3 but showing the grinding stationdiametrically opposite the one illustrated in Fig. 3. Fig. 6 is afragmental View representing the operation of grinding the other side ofthe teeth of the blank. Fig. 7 is a View taken in the plane of line 7-7of Fig. 17, showing one of the tracks or rails by means of which thecars are supported and guided. Fig. 8 is a view showing how the cars aresupported, guided and propelled intermediate the grinding stations. Fig.9 is a fragmental view illustrating a portion of the means for taking upplay between the master rack and-the master pinion. Fig. 10 is a viewshowing howthe cars are guided and propelled at each grinding station,also the means for causing the blank to roll past the grinding wheel.Fig. 10 may also be briefly described as a vertical sectional view takenin the plane of line 10--1O of Fig. 3. Fig. 11 is a lower side view ofthe parts shown in Fig. 9. Fig. 12 is a detail view of one of the cars.movable gib with which each car is provided, the view being taken in theplane of line 1313 of Fig. 24. Fig. 14 shows means tending to move thegib out of engagement with the coacting guide, the view being taken inthe plane of line 1l-14 of Fig. 24. Fig. 15 is a top plan view of one ofthe cars, showing also a portion of the means for guiding and-propellingthe car between the grinding stations. Fig. 16- is a frag-mentalsectional view taken in the plane of line 16-16 of Fig. 23, showing theguide for the upper portion of. the carriage and the guide for thepropelling chain. Fig. 17 is an outer side elevation of the parts shownin Fig. 15. Fig. 18isa fragmental view of the means for propelling thecars between grinding stations. Fig. 19 is a view of the hook byiuieansof which each car is yieldingly Fig. 13 illustrates the I connected tothe propelling chain. Fig. 20 is a fragmental plan view of the railwhich carries the weight of the bars between grinding stations. Fig. 21is a side elevation of the parts shown in Fig. 20. Fig. 22 is a planView of the guide for the upper portion of the car and of the guide forthe ropelling chain. Fig. 23 is a side elevation o? the parts shown inFig. 22. Fig. 24 is a fragmental side elevation of the grinding stationshown in Fig. 3. Fig. 25 is a horizontal sectional view taken in theplane of line 25-25 of Fig. 24. Fig. 26 is a f'ragmental end elevationof the machine taken from the right-hand end of Fig. 1. Fig. 27 is aview taken in the plane of line 2727 of Fig. 10, showing how playbetween the master rack and the master pinion is'pI'evented While oneside of each tooth is being ground. Fig. 28 is a fragmental elevationshowing how the movable gib on the car is moved into position to avoidstriking the end of the guide as the car enters a grinding station. Fig.29 is a view similar to that of Fig. 27, but showing how play betweenthe master rack and the master pinion is prevented while the oppositeside of each tooth is being ground, the view being taken in the plane ofline 2929 of Fig. 30. Fig. 30 is a View taken from the left-hand end ofFig. 29. It may also be described as a view taken in the plane of line3030 of Fig. 5. Fig. 31 illustrates the drive for the propelling chain.Fig. 32 shows a means for stopping the cars at the loading station. Fig.33 is a sectional view taken in the plane of line 33-33 of Fig. 2. Fig.34 is a plan view of the dressing mechanisms. Fig. 35 is a view taken inthe plane of line 35-35 of Fig. 34. Fig. 36 is an enlarged View showingthe operation of dressing the grinding wheel. Fig. 37 is a front view ofthe parts shown in Fig. 34-. Fig. 38 is a View taken from the right-handside of Figs. 34 and 37.

For the sake of brevity the gear wheels, sprocket wheels or otherarticles to be ground will be hereinafter referred to as blanks.

A machine embodying my invention may comprise a grinding wheel having onits periphery a series of equidistant annular ribs,

and means for rolling the blank across the pcriphery of the wheel. Forthe sake of accuracy in grinding and simplicity in dressing, thegrinding wheel is so constructed that only flat surfaces are utilizedfor grinding the teeth of the blanks. To this end, the grinding wheel isgiven a frusto-conical form, one side whereby the grinding of both sidesof each tooth is effected in two passages of the blank across theabrasive wheel. It will be evident from Figs. 4 and 6 that durin onepassage of' the blank the surfaces (1 constitute one side of each toothof an imaginary rack, and that during the other passage of the blank,said surfaces constitute the opposite side of said rack teeth.

The embodiment herein shown of the invention comprises two grindingwheels, one

adapted to take a roughing out and the other a finishing out. Thesewheels have a common axis and are arranged with their large sides facingeach other. Mechanism is provided for causing the blanks to travel pastdiametrically opposite portions of both of said wheels in succession.There are consequently four grinding stations designated A, B, C and Din Fi 1. The lacewhere the blanks are intro uced into t e machine andthe finished work removed will be termed the loading station E. Theroughing wheel is indicated at 1 and the finishing wheel at 2. Thesewheels are of relatively large diameter. The wheels 1 and 2 may bedriven in any suitable way, as, for' example, by means of belts (notshown) running'over pulleys 3 fixed upon the shafts that carry thegrinding wheels.

The blanks are indicated at b. Each blank is rigidly secured to an arbor0 (Fig. 8) by means of which the blank is supported during the grindingoperation and during its travel inthe machine, and through which rollingmovement is imparted to the blank while it is passing the grindingwheels. Each grinding wheel has the same number of grinding sur faces aas there are teeth on the blank; consequently, it is possible to passthreeblanks in close succession past the wheel. I there fore support theblanks on cars 4 (Figs. 8,- 10 and 12), each adapted to support threearbors 0. As best shown in Fig. 8, each arbor comprises a flange 5against whi'ch the blank may be rigidly clamped by means of a nut 6 onthe upper screw-threaded end of the arbor. 7 is a key for locating theblank in definite angular relation to the arbor. The flange 5 overliesthe upper end of the bearing in which the arbor 0 is rotatablysupported. referably a washer 8 of suitable material is interposedbetween the flange 5 and said bearing.

While passing the abrasive wheels, the cars 4 are supported upondove-tail guides 9 (Figs. 2, 10, 24 and 26) As shown in Fig. 10, thecars are provided with gibs 10 and 11 adapted to engage the dove-tailguides 9. Intermediate the guides 9, the cars are supported by meansincluding rails 12 (Fig. 8) of channel form. Each car is provided at itslower side with two casters 13 (Figs 8 and 12) adapted to run in therails 12, and thus carry the weight of the car. Each car also has twoguide rollers 14 mounted on vertical pivots and adapted to lie betweenthe vertical flanges of the channel rail 12. At the upper side of thecar 4 are two guide rollers 15 mounted on vertical pivots and lyingbetween the vertical flanges of two angular guide rails 16.

The lower gib 11 is movable with reference to the car 4 in order that itmay be moved into such position that the car-may pass onto the guide 9freely and without danger of said gib striking the end of the guide. Asshown 'in Fig. 13, the gib 11 lies upon a flange 17 on the car body, andis arranged to be moved laterally into engagement with the guide 9 bymeans of two screws 18 (Figs. 13 and 17) which extend freely throughholes in the gib and enter screw-threaded openings 19 in the car. Coiledexpansive springs 20 (Figs. 14 and 17) tend to move the gib away fromthe guide. The screws 18 are connected to turn synchronously by means oflovers 21 each rigid with one of the screws, the lower arms of saidlevers being connected by means of a link 22. To the upper arms of thelevers '21 are connected coiled contractile springs 21 which tend toturn the screws 18 in the direction to draw the gib 11 snugly againstthe guide 9. As the car approaches each guide 9, theg'ib 11 is releasedto movement by thesprings 20 (Fig. 14) by means of a cam bar 23 (Figs. 8and 28) located in position to be engaged by the leading end of the link22 and thus turn the screws 18. After the car; 4 has passed onto theguide 9, the link 22rides off thecam bar 23, whereupon the springs 21turn the screws 18 in the direction to draw up the gib 11 against theguide 9.

' The mcan's for moving the cars 4 while the blanks are being groundcomprises a long segmental nut on each car and one or more spirallythreaded elements, as, for example worms arranged at each grindingstation in position to engage said nut. Referring to Fig. 24, whichillustrates grinding station A, it will be noted that three worms 24 arenovided, said worms being secured to a shaft 25 which is driven by meansof a train of bevel gears 26 from a shaft 27 (Fig. 20). The worms at theopposite grinding station are driven from thesame shaft 27. The worms atthe grinding stations C and D are driven from a similar shaft 27 (Fig.1). The shafts 27 and '27" are connected through .ashaft 28. The shaft27 is driven from a shaft 29 (Fig. 33) through bevel gears 30.

The shaft 29 is driven through change gears 31 (Fig. 26) from a shaft 32carrying a spur gear 33 that meshes with a pinion 34 on the shaft of thegrinding wheel 1.

To the outer side of each car 4 is secured a bar 35 (Figs. 10 and 17)having a segment of a nut formed upon its outer side for engagement bythe worms 24. If desired, the leading end of said nut may be madeyieldable, as indicated in Fig. 25, by providing a pivoted section 35which is yieldingly held in alinement with the remainder of the nut bymeans of a spring 36.

The means for'causing the cars 4 to travel from one station to the nextcomprises an endless chain 37 (Figs. 8 and 17) mounted in what isvirtually an endless guide 38. The chain 37 is driven by meansof asprocket wheel 39 (Fig. 1) to the shaft of which is fixed a worm wheel40 (Fig. 33) that meshes with a worm 41 splined on a shaft 42. The shaft42 is driven from the shaft 28 by means of bevel gears 43.

Each car is releasably connected to the chain 37 by means of a hook 44(Figs. 18 and 19). Said hook is pivoted upon the axis of the leadingguide roller 15 and is urged into position to be engaged by the rollersof the chain 37 by means of a torsion spring 45. Shortly after the carhas reached the point at which it will be driven by one of the worms 24the hook 44 is moved away from the chain 37 and held out of engagementtherewith by means of a cam bar 46 (Fig. 3) secured to the guide 38 inposition to engage a stud 47 on the hook 44. At the time when the carpasses out of engagement with the last worm 24, the cam bar 46 allowsthe hook 44 to swing into position to be picked up by the chain 37,whereupon the car is moved to the next station. I

Referring now to Fig. 31: It will be noted that the teeth of thesprocket wheel 39 do not engage every roller of the chain 37 but onlyevery other roller. Consequently, if a tooth of said sprocket shouldforce the hook 44 away from a given roller the hook will spring intoengagement with the next succeeding roller.

The movement impart-ed to the cars 4 by the chain 37 is much faster thanthat produced by the worms 24, and enough cars are provided so thatthere shall always be a car waiting to enter a grinding station. Thehook 44 is suificiently shallow so that when a car strikes another caralready stopped the chain 37 slips by the hook. Onthe rear end of eachcar is a spacing. stud or buffer 48 (Fig. 12) which serves to hold thecars properly spaced apart when grouped at the various stations. 1

The means for rolling the blanks past the grinding wheels includes amaster gear wheel fixed with relation to each blank and arranged to meshwith a master rack located at each grinding station. Upon reference toFigs. 8 and 10, it will be observed that a master gear wheel 50 is keyedupon the arbor c in position to mesh with a master rack 51. The masterrack 51 is mounted for longitudinal adjustment in a. guide or support.52(Figs. 10 and 25). To one end of to revolve or roll over the peripheryof the grinding wheel, so as to present one side of each tooth of theblank. to a grinding surface a.

Means is provided for taking up back-lash or play between the masterpinion and the master rack. When one side of the tooth is being ground,back-lash is prevented by applying a brake to the master pinion so thatthe master pinion teeth shall be pressed against one side of the teethof the master rack; and when the other side of .the teeth of the blankis being ground, back -lash is prevented by frictionally driving themaster pinion so as to hold the pinion teeth against the1 opposite sideof the teeth of the master rac Referring now to Figs. 8 and 10, it willbe noted that apinion 55 is rotatably mounted upon the arbor 0 below themaster pinion 50, the pinion 55 being yieldingly pressed against thelower side of the master pinion 50 by means of a coiled expansive spring56 and a brake disk 57. The tension of the spring 56 may be adjusted bymeans of a nut 58 on the lower end of the arbor. A dog 59 (Fig. 11)mounted on the carriage 4 to swing on the axis 60 is adapted to engagethe teeth of the pinion 55. A torsion spring 61 (Fig. 9) tends to swingthe dog 59 into engagement with said pinion. 62 is an arm rigid with thedog 59 and carrying a roller 63 arranged to he engaged by two cam bars64 located at grinding stations Band D, said cam bars serving towithdraw the dogs 59from the pinions 55. These cam bars are shown inFigs. 26, 29 and 30. At said grinding stations there are providedtwo'stationary racks 65 (Figs. 29 and 30) adapted to mesh with thepinions 55. As clearly shown in Fig. 8, the pinions 55 are slightlysmaller in diameter than the master pinions 50.

While the blank is passing grinding station A, the dog 59 is inengagement with the pinion 55. By reason of the resulting resistance torotation of the master pinion 50, the teeth of said master pinion areheld against one side of the teeth of the master rack 51, thuspreventing play between the master rack and the master pimon. While theblank is passing grinding station B, the dog 59 is held out ofengagement with the pinion 55 by means of the cam bar 64, and the pinion55 meshes with the stationary rack bar 65. Inasmuch as the master pinionis of greater diameter than the pinion 55. the rack 65 tends to roll themaster pinion 50 at a greater peripheral speed than that due to themaster rack 51. Consequently, the teeth of themaster pin on are heldpressed against the opposite side of the teeth of the master rackfromthat engaged while passingstation A. Similarly, while passingstation C,- the dog 59 holds the pinion against rotation; and at stationD the pinion is driven by the rack 65.

The grinding wheels 1 and 2 may be located at any desired distance fromeach other which will allow suitable space for the. loading station E.Any preferred means may be employed to stop the cars at the loadingstation. Herein is'shown a plate 66 (Flg. 1 attached to the aide 38,said plate havmg a cam surface ailapted to be engaged by the stud 47 todisengage the hook 44 from the chain 37, said plate also having anangular stop portion lying in the path of sa d stud. When a car stops atthe loading statlon, the operator replaces the ground gears with gearsto be ground, and swmgs the hook 44 outwardly until the stud 47 is clearof the stop plate 66, whereupon a car which has previously come up tothe car at the loading station pushes the last-mentioned car along untilits hook 44 is picked up by the chain Herein is shown a hook 67 (Flgs. 1and 3) located at the entering side of each grinding station, said hookbeing plyotally mounted upon the aide rail 38 m posltion to engage andarrest tile stud 47 (Figs. 8 and 12 of an approaching car. The hooks 67may e conneeted for simultaneous actuation by any preferred means, as,for example, two links 68, and a hand lever 69, sald hand lever beingpivoted at 70 and having a pm-"and-slot connection with said links for areason to appear hereinafter. The double stepped stop plate 69' (Fi s.3, 10 and 24) is a plate on the chain gui e 38 against which the lever69 is held in either of two positions. The upper stop 69 for theinoperative positlon of the hooks 67 is shown against the lever 69 inFig. 3. The lower stop 69 serves to lock the hooks 67 in operativeposition. It will be seen that by swinging the mud lever 69 to theright,-as viewed in Fig. 1, the hooks 67 will be swun into the path ofthe studs 47 of approae ing cars, so that when said studs engage thehooks 67, the hooks 44 of said cars will be moved out of engagement withthe endless chain 37. The engagement of the hooks 67 with the studs 47,serves to arrest the cars 4 and hold them against movement due to thepressure of following cars. The hooks 44 are sufficiently shallow sothat the chain 37 ma slip past the books 44 of the cars detaine by thecars which are arrested by the hooks 67.

\Vhile various means may be employed to dress the plane grindingsurfaces a, there has been selected for illustration the means shown inFigs. 34 to 38, inclusive. Two brackets 71 are secured in the lnainframe at opposite sides of each grinding wheel. To the upper ends of thebrackets 71 is fixed a table 72 extending across the peri hery ot thegrinding wheel. A cross sli e 73 is mounted on a guide 74 on the table72 for movement parallel with the axis of the grimling wheel. Anysuitable means may be employed to move the cross slide 73 on the guide74, as,for example, an ordinary adjusting screw 75, there being agraduated dial 76 connected with said screw for convenience in adjustingthe cross slide to a known extent.

A slide 77 is mounted on a guide-78 on the cross slide 73 for movementperpendicularly to the axis of the grinding wheel and parallel to theplane rinding surfaces a, such movement being eli'ected by means of anordinary adjusting screw 79 or the like. The slide 77 carries, in thisinstance, a series of dressing points 80 (Figs. 35 and 36) correspondingin number to the grinding surfaces (1. In the construction herein shown,each dressing point 80 is secured to one arm of a lever 81 which ispivoted upon a stud 82 rigidly mounted on the slide 77 The other arm ofsaid lever is provided with a gear segment 83 that meshes with a gearsegment 84 rotatably mounted on the bed 77. The segment 84 has a squaredend 85 by means of which the segment may be turned to effect a niceadjustment of the dressing point 80. The dressing points may be securedin adjusted position by suitable means such as a clamping bar 86overlying the hubs 87 of the levers 81, said bar being held pressedtightly against the ends of said hubs by means of screws 88.

After repeated dressing operations it will eventually become necessaryto remove the grinding wheel, dress off the periphery of the wheel andform new plane grinding surfaces a. The wheel may then be replaced inthe grinding machine. After each such operation, it is necessary toadjust the means for supporting and rolling the blanks to compensate forthe decrease in diameter of the wheel. To this end the rails 12, 16 and38 are mounted on brackets 89 (Figs. 1, 2, 8 and 33) which are securedto sub-bases 90, which are secured to the bed 91 of the machine foradjustment per )endicularly to the Inn itudinal center line 0 said bed.The means or guiding said sub-bases and for securing them in adjustedposition may be of any suitable charbars 64 (Fig, 29) are carried bybrackets 99.

(Fig. on the slides 97. Any suitable means may be employed to adjust.the slides 97 and hold them in adjusted positlon, as, for

' example, an ordinary adjusting screw 100.

In order that the two sides of the framework which constitutes the guidemeans for the cars 4 may be moved toward each other to compensate fordecrease in the diameter of the grinding wheels due to wear and dressing, the rails 12, 16 and 38 at each end of the machine are made in twohalves, and the ends of the sections of each rail are slotted as shownin Figs. 7 17 and 20 to 23, inclusive, so as to provide virtually atongue and groove connection allowing of adjustment toward and away fromthe longitudinal center line of the machine.

Adjustment of the length of the chain 24 to correspond with adjustmentof the guides toward and away from the center line of the machine isefiected by removing or adding one or more links.

The bevel gears on the shafts 27 and 27 (Fig. 24) are splined to permitthe adjust ment of the brackets 89. Likewise, the pin and slotconnection in lever 69 to links 68 and the splined worm 41 on the shaft42 permit the same adjustment.

The operation of the machine may be briefly described as follows:

In Fig. 1, the parts are shown in the position occupied shortly afterthe hand lever 69 has been operated to release the'cars 4. If

we follow the travel of the car marked a: in

Fig. 1, we find that as it passes grinding station A, one side of eachtooth of each of the three blanks on said car'are ground, and that asthe rearmost of the three blanks passes.

clear of the grinding wheel 1, the stud 47 of said car passes off thecam bar 46 (see the dotted position illustrated in Fig. 3), thusallowing the hook 44 to swing into engagement with the continuouslymoving chain 37. The chain 37 advances the car until said car overtakesone of the cars which is waiting in line to enter grinding station B.While the speed of the chain 37 is much faster than the rate of movementimparted to the cars by the worms 24, its speed is sufliciently slow sothat a car advanced by the chain does not collide with objectionableforce with a car which is being retarded by a car at a grinding station.

While the car as was passing the grinding station A, the dogs 59 were inengagement with the pinions 55, thus acting to take up play between themaster pinions 50 and the master rack 51.. While the carriage m is passing the grinding station B, the opposite side of each tooth of theblanksis being ground, and play betwen the master pinions and the master rackis taken up by'driving the pinions 55 through the medium of the rack 65.As indicated in Fig. 29, the dog 59 is disengaged from the pinion 55 bythe cam bar 64, just before the pinion 55 meshes with the rack 65.

As will be understood from Figs. 5, 24 and 25, the car 4 is engaged byone of the worms 24 before the'hook 44 has been disengaged from thechain 37 by the cam bar 46. During the interval between the times whenthe worm 24 and the cam bar 46 become efl'ective, the hook 44 yields toallow the chain 37 to pass.

When passing the stations C and D, the blanks are finish-ground and arethus ready to be removed from the arbor 0 upon reaching the loadingstation E.

When dressing becomes necessary, the operator operates the lever 69(Fig. 1) to place the hooks 67 in position to throw out and arrest thehooks 44 of the next approaching car at each grinding station. After thecars that were in the grinding stations have passed out, the operatoradjusts the cross slide 73 (Fig. 38) to the necessary extent, and thenadvances and retracts the slide 7 7 thus causing the dressing points 80to true up the grinding surfaces at. The master racks 51 (Fig, 25) arethen adjusted by means of the screws 53 to an extent corresponding tothe extent of adjustment of the cross slide 73. The stops 67 (Fig. 1)are then Withdrawn, whereupon the cars begin to move into the grindingstations.

It should be distinctly understood that the machine herein shown is butone of various possible embodiments of my some or all of the advantagesof the invention may be obtained by means of other relative arrangementsof the grinding wheels, and that numerous changes in the constructionand arrangement of the work-guiding and propelling means maybe madewithout departing from the invention defined in the appended claims.

I claim as my invention:

1. The combination of a frusto-conical grlnding wheel having upon itsperiphery a plurality of equidistant annular plane grinding surfaces,and means for rolling a toothed blank across the periphery of said wheelwith the teeth of the blank in contact with said plane rinding surfaces.

2. T e combination of afrusto-conical grinding wheel having upon itsperiphery a invention, that pluralit of equidistant annular planegrinding sur aces, and means for rollin a toothed blank twice across theperiphery 0 said wheel to present one side of each tooth to said planesurfaces in the first passage and the opposite side of said teeth in thesecond assage.

3. The combination of a rusto-conical grinding wheel having upon itsperiphery a luralit of equidistant annular plane grinding sur aces, andmeans for rolling a toothed blank across the periphery of said wheel atdiametrically opposite points.

4. The combmation of a grinding wheel, means for feeding blanks past onepart of said wheel and for returnin them past another part of saidwheel, an means for roll ing the blanks as they are fed .past the wheel.

5. The combination of two frusto-conical grinding wheels each havingupon its periphery a plurality of equidistant annular plane grindingsurfaces, said wheels having a common axis and being'positioned withtheir larger sides facing each other, means for causing toothed blanksto travel past diametrically opposite points of both of said wheels, andmeans for rolling the blanks as they pass the wheels.

6. The combination of two frusto-conical grinding wheels each havingupon its periphery a plurality of equidistant annular plane grindingsurfaces e ual in number to the number of teeth on t e blank to beground, and means for rolling said blank acrossthe peripheries of saidwheels, whereby one side of each tooth is ground on one wheel and theother side of each tooth is ground on the other wheel.

7. Means forming a plurality of rotary equidistant annular plane grindlnsurfaces each perpendicular to its axis 0 rotation,

and means for rolling a toothed blank along said surfaces to .lace eachtooth in engagement with one of sai plane grinding surfaces, the path ofsaid blank being at an angle to the axis or axes of rotation of thegrinding surfaces.

8. A gear-grinding machine having, in combination, a peri lierallyribbed. grinding wheel of relatively arge diameter and wide peripheralface, and means for rolling a gear wheel across the periphery of saidgrinding wheel with the ribs in generating relation to the gear teeth.

9. A machine com rising, in combination, a metal-removing w eel havingperipheral tooth-generating surfaces, the peri hery of said wheel beingof sufiicient widt to act u on a plurality of blanks simultaneously, a

urality of cars each having a plurality of lank-supporting arbors, meansfor circulating sal cars to move them to and away from said 'wheel, andmeans for rolling the blanks over said tooth-generating surfaces.

10. A machine comprising, in combination,

metal-removing means having tooth-generating surfaces and being ofsufiicient width to act upon a plurality of blanks simultaneously, aplurality of cars each having a plurality of blank-supporting arbors,means for circulating said cars to move them to and away from saidmetal-removin means, spirall threaded means arrange adjacent to saimetal-removing means, each of said cars being arranged to be engaged bysaid spirally threaded means, the latter being arranged to move the carspast the metal removing means,

said circulating means being arran ed to deliver the cars to saidspirally threa ed means and receive them therefrom, a master rackarranged parallel with said spirally threaded means and adjacent to saidmetal-removing means, and a master pinion on each of said arborsarranged to mesh with said master rack to roll the blanks over saidtooth-generating surfaces.

11. A machine comprising, in combination metal-removing means havingperi heral tooth-generating surfaces and being 0 sufficient width to actu on a plurality of blanks simultaneously, a urality of cars each havina pluralit of blank-supportin arbors, spirally threa ed means arranged aj acent to said metal-removing means, each of said cars' having a rackarranged to be engaged by said spirally threaded means, the latter beinarranged to move the cars past the meta removing means, means to deliverthe cars to said spirally threaded means and receive them therefrom, amaster rack arranged parallel with said spirall threaded means andadjacent to said meta -removing means, and a master pinion on each ofsaid arbors arran ed to mesh with said master rack to roll t e blanksover said tooth-generating surfaces.

12. A machine comprising, in combination, a cutter havin peripheraltooth-generating surfaces'and 0 sufficient width to act upon a pluralityof blanks simultaneously, a car having a plurality of blank-supportinarbors, spirally threaded means arrange adjacent to said cutter, saidour having a rack arran ed to be en aged by said spirally threa edmeans, thedatter being arranged to move the car past the cutter, amaster rack arranged ara lel with said spirally threaded means anadjacent to said cutter, and a master inion on each of said arborsarranged to mes with said master rack to roll the blanks over saidtooth-generating surfaces.

13. A machine having, in combination, a plurality of work-supportingcars, means for directing said cars to move in a circuit, said meansincluding a guide,'a gib on each car for holding the car in engagementwith the guide, and means for moving said gib into proper position toclear the uide as the car is about to enter upon the gui e.

14. A machine comprising, in combination, being sufiiciently great sothat it may act upon a grinding Wheel having peripheral tooththe entireperipheral face of the blank in one generating surfaces, the diameter ofsaid revolution of the blank. 1 wheel being many times greater than theln testimony whereof, I have hereunto afthiokness of the gear to begenerated, and fixed my signature.

means for rolling a blank over said t00thgenerating surfaces, the widthof said wheel HOWARD D. COLMAN.

